The present invention is directed to a method for making and using arrays of short, small cross section wires or pins as pin fin heat exchangers. The heat exchangers are particularly useful for cooling electronic chips. The present invention provides a way of achieving mass produced arrays of high efficiency heat exchangers or heat sinks which are low cost compared to the conventional heat sinks produced by liquid or reactive ion etching of silicon. In addition, the pin arrays compensate for any uneven thermal expansion or contraction between the manifold and the chip. Furthermore, the arrays may be made in various shapes and sizes for meeting various application requirements.